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vbcc [2024/05/09 13:57] – [Optimizations] pulkomandyvbcc [2024/08/27 17:20] (current) – [The configuration file] Fix typos, add missing asv pulkomandy
Line 50: Line 50:
     * lib/     * lib/
       * startup.o       * startup.o
 +      * libvc.a
 +    * include/
 +      * ctype.h
 +      * stdlib.h
 +      * string.h
     * vlink.cmd     * vlink.cmd
  
 +The content of each file or how to generate them is detailed below.
 ===== The configuration file ===== ===== The configuration file =====
  
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 -cc=vbccunsp -I"$VBCC"/targets/unsp-vsmile/include -quiet %s -o= %s %s -O=%ld -cc=vbccunsp -I"$VBCC"/targets/unsp-vsmile/include -quiet %s -o= %s %s -O=%ld
 -ccv=vbccunsp -I"$VBCC"/targets/unsp-vsmile/include %s -o= %s %s -O=%ld -ccv=vbccunsp -I"$VBCC"/targets/unsp-vsmile/include %s -o= %s %s -O=%ld
--as=vasmunsp_std -quiet -Fvobj %s -o %s+-as=vasmunsp_std -quiet -ile -Fvobj %s -o %s 
 +-asv=vasmunsp_std -ile -Fvobj %s -o %s
 -rm=rm %s -rm=rm %s
 -rmv=rm %s -rmv=rm %s
--ld=vlink -ole -b rawbin1 -Cvbcc -T"$VBCC"/targets/unsp-vsmile/vlink.cmd -L"$VBCC"/targets/unsp-vmsile/lib "$VBCC"/targets/unsp-vsmile/lib/startup.o %s %s -o %s +-ld=vlink -ole -b rawbin1 -Cvbcc -T"$VBCC"/targets/unsp-vsmile/vlink.cmd -L"$VBCC"/targets/unsp-vsmile/lib "$VBCC"/targets/unsp-vsmile/lib/startup.o %s %s -o %s -lvc 
--ldv=vlink -ole -b rawbin1 -Cvbcc -T"$VBCC"/targets/unsp-vsmile/vlink.cmd -L"$VBCC"/targets/unsp-vmsile/lib "$VBCC"/targets/unsp-vsmile/lib/startup.o %s %s -o %s -Mmapfile +-ldv=vlink -ole -b rawbin1 -Cvbcc -T"$VBCC"/targets/unsp-vsmile/vlink.cmd -L"$VBCC"/targets/unsp-vsmile/lib "$VBCC"/targets/unsp-vsmile/lib/startup.o %s %s -o %s -lvc -Mmapfile 
--l2=vlink -ole -b rawbin1 -Cvbcc -T"$VBCC"/targets/unsp-vsmile/vlink.cmd -L"$VBCC"/targets/unsp-vmsile/lib %s %s -o %s +-l2=vlink -ole -b rawbin1 -Cvbcc -T"$VBCC"/targets/unsp-vsmile/vlink.cmd -L"$VBCC"/targets/unsp-vsmile/lib %s %s -o %s 
--l2v=vlink -ole -b rawbin1 -Cvbcc -T"$VBCC"/targets/unsp-vsmile/vlink.cmd -L"$VBCC"/targets/unsp-vmsile/lib %s %s -o %s -Mmapfile+-l2v=vlink -ole -b rawbin1 -Cvbcc -T"$VBCC"/targets/unsp-vsmile/vlink.cmd -L"$VBCC"/targets/unsp-vsmile/lib %s %s -o %s -Mmapfile
 </code> </code>
  
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         .empty: { RESERVE(0x4000); } > lorom         .empty: { RESERVE(0x4000); } > lorom
         .rodatal: { *(.rodata) } > lorom         .rodatal: { *(.rodata) } > lorom
-        .rodata: { *(.rodata) } > rom+        .rodata: { *(.rodata) *(.rodata2) } > rom
         .textl: { *(.text) } > lorom         .textl: { *(.text) } > lorom
         .text: { *(.text) } > rom         .text: { *(.text) } > rom
Line 111: Line 118:
         __BL = SIZEOF(.bss);         __BL = SIZEOF(.bss);
         __DS = ADDR(.data);         __DS = ADDR(.data);
 +        __DD = LOADADDR(.data);
         __DL = SIZEOF(.data);         __DL = SIZEOF(.data);
  
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         ; Copy the initialized variables into RAM         ; Copy the initialized variables into RAM
         ; __DL = length of variables section         ; __DL = length of variables section
-        ; __DS = start of variables section in ROM +        ; __DS = start of variables section in RAM 
-        LD R1, 0x0000 +        ; __DD = start of variables section in ROM 
-        LD R2, __DS+        LD R1, __DS 
 +        LD R2, __DD
         LD R3, __DL         LD R3, __DL
         JZ gomain         JZ gomain
Line 201: Line 210:
 gomain: gomain:
         GOTO main         GOTO main
 +
 +; Handlers for indirect calls. Used by VBCC to handle function pointers, because unSP does not have
 +; an indirect call (CALL R1 or similar) operation and it is not trivial to emulate one.
 +.globl __indirect_R1
 +.globl __indirect_R2
 +.globl __indirect_R3
 +.globl __indirect_R4
 +__indirect_R1:
 +        LD PC,R1
 +__indirect_R2:
 +        LD PC,R2
 +__indirect_R3:
 +        LD PC,R3
 +__indirect_R4:
 +        LD PC,R4
  
 ; The interrupt vectors section, contains pointers to the interrupt handlers ; The interrupt vectors section, contains pointers to the interrupt handlers
Line 239: Line 263:
  
 Note: the -ile option tells vasm that files included using the incbin directive are in little endian. This gives the same results as the official unSP toolchain when importing binary files. Note: the -ile option tells vasm that files included using the incbin directive are in little endian. This gives the same results as the official unSP toolchain when importing binary files.
 +
 +===== The C library =====
 +
 +vbcc does not come with an open source C library. A full one from other sources could be compiled, but we don't need a complete C library.
 +
 +So here is a very minimal one with enough support to run the compiler and to run Contiki, which has minimal needs from the C library (just a few string functions).
 +
 +<code c>
 +/*
 + * Copyright (C) 2024 Adrien Destugues <pulkomandy@pulkomandy.tk>
 + *
 + * Distributed under terms of the MIT license.
 + */
 +
 +int strlen(const char* str)
 +{
 +        int i = 0;
 +        while(*str++) i++;
 +        return i;
 +}
 +
 +int isprint(char c)
 +{
 +        return c >= 32;
 +}
 +
 +void strcpy(const char* src, char* dst)
 +{
 +        char c;
 +        while (c = *src++)
 +                *dst++ = c;
 +        *dst = 0;
 +}
 +
 +void memset(int* s, int v, int n)
 +{
 +        while(--n >= 0)
 +                *s++ = v;
 +}
 +
 +int strncmp(const char* a, const char* b, int n)
 +{
 +        while(--n >= 0) {
 +                if (*a != *b)
 +                        return *a - *b;
 +                if (*a == 0)
 +                        return *b;
 +                if (*b == 0)
 +                        return -*a;
 +        }
 +}
 +
 +int __div(int a, int b)
 +{
 +        int c = 0;
 +        while (a >= b) {
 +                a -= b;
 +                c++;
 +        }
 +        return c;
 +}
 +
 +int __mod(int a, int b)
 +{
 +        while (a >= b) {
 +                a -= b;
 +        }
 +        return a;
 +}
 +</code>
 +
 +To generate the libc.a file:
 +
 +<code sh>
 +vc +vsmile -nostdlib -O3 -c libc.c
 +ar cru libvc.a libc.o
 +</code>
 +
 +We also need some include files. ctype.h and stdlib.h can be empty, but they are used by Contiki so they must exist.
 +
 +string.h has some basic functions declarations and type definitions:
 +
 +<code c>
 +#ifndef __STRING_H
 +#define __STRING_H 1
 +
 +/*
 +  Adapt according to stddef.h.
 +*/
 +#ifndef __SIZE_T
 +#define __SIZE_T 1
 +typedef unsigned int size_t;
 +#endif
 +
 +#undef NULL
 +#define NULL ((void *)0)
 +
 +/*
 +  Many of these functions should perhaps be implemented as
 +  inline-assembly or assembly-functions.
 +
 +  Most suitable are:
 +  - memcpy
 +  - strcpy
 +  - strlen
 +  - strcmp
 +  - strcat
 +*/
 +void *memcpy(void *,const void *,size_t n);
 +void *memmove(void *,const void *,size_t);
 +void *memset(void *,int,size_t);
 +int memcmp(const void *,const void *,size_t);
 +void *memchr(const void *,int,size_t);
 +char *strcat(char *,const char *);
 +char *strncat(char *,const char *,size_t);
 +char *strchr(const char *,int);
 +size_t strcspn(const char *,const char *);
 +char *strpbrk(const char *,const char *);
 +char *strrchr(const char *,int);
 +size_t strspn(const char *,const char *);
 +char *strstr(const char *,const char *);
 +char *strtok(char *,const char *);
 +char *strerror(int);
 +size_t strlen(const char *);
 +char *strcpy(char *,const char *);
 +char *strncpy(char *,const char *,size_t);
 +int strcmp(const char *,const char *);
 +int strncmp(const char *,const char *,size_t);
 +int strcoll(const char *,const char *);
 +size_t strxfrm(char *,const char *,size_t);
 +
 +#endif
 +</code>
 ====== Running the compiler ====== ====== Running the compiler ======
 +
 +Note: make sure you have set the VBCC environment variable as explained earlier, otherwise the compiler will not find the target configuration and will complain and not compile anything.
  
 To compile a .c file into a .o file: To compile a .c file into a .o file:
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   mame -debug -debugger qt -rompath /path/to/vsmile/bios/ vsmile -cart ./cartridge.bin -nomax   mame -debug -debugger qt -rompath /path/to/vsmile/bios/ vsmile -cart ./cartridge.bin -nomax
      
 +  
 +====== Generating debug symbols for MAME ======
 +
 +Use the -v option to vbcc to enable verbose mode, this will also generate a mapfile containing info about the generated binary.
 +
 +The mapfile list of symbols can be turned into a file that the MAME debugger can use to create comments:
 +
 +  sed mapfile -ne 's!  0x\(.*\) \(.*\):.*!comadd \1,\2!p' > symbols.mame
 +
 +Then in MAME, use "source symbols.mame" to load it. You can switch the disassembly view to show comments, and it will be very helpful to understand where you are when stepping through the code. Even local labels are exported, which can be matched with .ic2 files to compare the intermediate representation with the generated code. Very useful when debugging the compiler.
 ====== TODO list ====== ====== TODO list ======
  
 ===== Bugs ===== ===== Bugs =====
  
-  * There is an internal compiler error when compiling the sound demo +  * <del>There is an internal compiler error when compiling the sound demo</del> 
-  * long int values are completely untested +  * long int values are mostly untested and broken in various places (code is missing, they will be handled the same as 1-byte values) 
-  * Try to compile larger projects such as Contiki and Copyright Infringement to find more bugs+  * <del>Contiki crashes when trying to call a function pointer</del> 
 +  * <del>Probably more problems waiting in Contiki once that is fixed</del> 
 +  * Try to compile larger projects such as Copyright Infringement to find more bugs
  
 ===== Memory addressing ===== ===== Memory addressing =====
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 ===== Startup and library ===== ===== Startup and library =====
  
-  * The startup script should clear the bss segment to 0 +  * The startup script should clear the bss segment to 0 (MAME will do this on first start, but not on reset) 
-  * Move the implementation of ''__div'' and ''__mod'' into libvc and implement them also for "long" types+  * Implement division and modulo for "long" types, signed vs unsigned, etc.
   * Floating point support routines   * Floating point support routines
   * Move font.bin outside of crt0/startup, and provide a more convenient way to handle resources (some Makefile rules maybe?)   * Move font.bin outside of crt0/startup, and provide a more convenient way to handle resources (some Makefile rules maybe?)
vbcc.1715263042.txt.gz · Last modified: 2024/05/09 13:57 by pulkomandy
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